Process of molding bricks.



H. SGHULTE-STEINBERG.

PROCESS OF MOLDING BRICKS.

APPLICATION FILED APR. 6, 1909.

971 693 Patented 0013.4, 1910.

erases.

. rrnn STATES PATENT OFFICE.

HUGO SCHULTE-STEINBERG, D'UREN, NEAR STOCKUM, GERMANY.

PROCESS OF MOLDING BRICKS.

Specifics tion of Letters Patent.

Patented Oct. 4, 1910.

Application filed April 6, 1909. Serial No. 488,243;

of the particles of the mass in practice always exceeds the maximum ofmoisture allowable for the purpose of burning the bricks directly afterpressing'them.

In the moist clay, used for molding bricks, the water is contained intwo forms, which should be held apart in considering the moldingprocess. Firstly, there is the surface water, which envelops the singleparticles, and secondly, there is the saturation water, which fills theinterior of the particles owing to capillary action. This saturationwater does not take part in the function of the water asa lubricant or abinding agent, during the molding process, the surface water only beingeffective. But as during burning of the molded mass, the entire moisturemust be driven off, the sum of both waters must again be hereconsidered. In other words, for pressing and for the mechanical cohesionof the molded mass the saturation water is useless, while for burning itis injurious. Now, with the previously practiced dry press processes,the minimal quantity of the surface water used for binding andlubricating, plus the saturation water carried along as ballast, wasgreater than would permit direct burning. To overcome this objection,the clay was dried more thoroughly than permitted by the minimalquantity of surface water, and was then compressed so strongly that thesaturation water would, in part at least, be forced to the surface, tothus assume the function of binding and lubricating agent. But it wasjust this enormous high pressure which has rendered such processespractically useless.

The present invention primarily consists in a process of dry-pressingclay --bricks, wherein the amount of moisture in the clay is reduced, byheating, to a minimum quantity' which remains in the clay in the form ofsteam, whereupon the clay is molded and then immediately burned. Theevaporation may be effected by passing hot gases through the mass,preferably waste-gases from the kiln. In clay saturated with water, thewater filling the pores of the mass acts neither.

as a lubricant nor as a binding agent for holding together the particlesuntil the mass isburned; on the other hand, this water greatlyinterferes with the drying process in the kiln. According to the presentinvention so much of this water is removed by evaporation as has theeffect of reducingthe ductility and adhesiveness of the mass. Theresidual moisture, in the form of steam, is in part condensed during themolding of the hot mass, and envelope the individual particles, so thatthe molding can be readily effected. If the molded clay is placed in thekiln while stillhot, only a very small residue of moisture remains to beexpelled before the burning process can take place. Another advantage offilling the pores of the mass with steam lies in the fact that the airisby this means expelled. It is well-known that the presence of air. inthe dry-molded mass is liable to result in the formation of cracks andcrevices, the air being compressed during the molding operation, andthen suddenly expanding with the result referred to. Steam present inthe pores is condensed to water during the molding operation and doesnot rexpand thereafter, until the moisture is gradually evaporated inthe kiln, without deleterious effects. expulsion of the moisture byevaporation causes the-same to be very uniformly distributed in themass. The molded clay comes exceedingly well through the burningoperation, and the finished brick is smooth, even, and of homogeneousstructure.

Apparatus for carrying outthe improved method of manufacture is shown inthe annexed drawing, partly in section.

In the drawing 10 represents an inclined mixing drum rotatable onrollers11 and 12 and adapted to be driven by means of gearwheels 13, shaft 14and pulleyv 15. At the delivery end of the drum there is a chamber 16communicating by means of a pipe 17 with the up-take of the kiln 18. Atthe head of the drum there is a chamber 19 communieating by means of apipe 20 with a chimney not shown in the drawing. The chamber 19 isprovided with a hopper 21, to which clay is delivered by abucket-'conveyer 22from a The pit 23. A rail-track 24 for trolleys 25leads to this pit Grinding mechanism 26 is' arthis sieve there is ahopper 33 which delivers to a molding'press 34. The coarse materialretained by the sieve returns through a con-' Crude clay duit 35 to thechamber 16. brought by the trolleys 25 is tipped into the pit 23 andthence conveyed by the conveyer 22 to the hopper 21 and drum 10. in thelatter the clay is well mixed and heated by the gases which flow fromthe kiln 18 through pipe 17 and chamber 16 to the delivery end of thedrum. These gases move in the direction opposed to the advance or theclay in the drum, so that the clay be comes well heated and so much ofits water is removed by evaporation as has the'eiiect of reducing theductility and adhesiveness of the mass. The resultant vapor passes withthe smoke-gases through chamber 19 and pipe 20 to the chimneyhereinbefore referred to. The heated mass is ground by the rollers 26and conveyed to the trough 30, sieve 31 and hopper 33, the coarser partsbeing retained by the sieve and returned to the chamber 16 in order tobe regrou1'1d. The molding press 34 automatically takes in and molds theground clay, the residual moisture in the clay, which is retained in theform of steam, being in part condensed during the molding of the hot mass, to envelop the individual particles, so that the molding can bereadily efiected. The molded bricks can 'immediately be placed in thekiln 18.

The utilization of waste-heat of the kiln for heating the crude clay isan advantage from the economical point of View, but

evacea the clay into steam, driving 011 part of the steam thus formed,molding the hot clay while impregnated with the residual steam, andkilnrdrying the molded clay.

2. Process of molding heated clay, which consists in bringing heatinggases into direct contact with the moist clay, said gases-carryingenough heat-to turn the water carried by the clay into steam, drivingofi part of the steam thus formed, molding the hot clay andsimultaneously condensing the residual steam during the molding process,and kilndrying the molded clay.

3. Process of dry-molding clay for the manufacture of bricks, consistingin heating the crude clay, converting the moisture contained in the clayinto steam,'by conducting the waste-gases from the kiln through thecrumbled and intimately mixed cla sifting the ground mass and returningto t e grind ing mechanism the coarse particles retained by the sieve,molding the hot clay, while impregnated with steam and placing thebricks in the kiln.

Signed by me at Barmen, Germany, this 16th day of March 1909.

HUGO SCHULTE-STEINBERG.

Witnesses:

O'rro Komo, PAUL Murmur.

